Reaction products of alkali metal meborate and hydrocarbon substituted succinimide

ABSTRACT

Compositions are provided useful in lubricating oil for detergency, dispersancy, antiwear and acid neutralization, which are the reaction product of an alkali metal metaborate and a succinimide in the presence of water, the presence of excess alkali metal metaborate being contemplated.

United States Patent Lowe Sept. 2, 1975 [54] REACTION PRODUCTS OFALiKALI METAL 328L428 l0/l966 LeSuer 260/3263 MEBORATE AND HYDROCARBON3.282.955 ll/l966 LESUCI'H 260/3263 3.3l3 727 4/1967 Peeler 260/534SUBSTITUTED SUCCINIMIDE 3,322.670 5/l967 Burt et al .i 260/3263 [75]Inventor: Warren Lowe, El Ccrrit0 Califi 3.344.069 9/[967 Stuebc 252/4963.449362 6/1969 Lee 260/3263 [73] Assignee: Chevron Research Company,San

Francisco, Calif. Primary I:'.\uminer-J0hn F. Terapane [22] Ffled' 1974Attorney, Agent/or FirmG. F. Magdeburger; C. J. [21] Appl. No.: 438,966Tonkin Related US. Application Data [60] Continuation of Ser. No.163.542, July 14, l97l.

abandoned. which is a division of Ser. No. 31,4]2. [57] ABSTRACT April23. 1970. Pat. NO. 3,666.662.

Compositions are provided useful in lubricating oil for 52 U.S. Cl260/534 R detergency dispersancyand acid neumlim' I C07c 103/44 tion,which are the reaction product of an alkali metal 88] Field of Search260/534 R metabome and succinimide the Presence ter, the presence ofexcess alkali metal mctaborate [56] References Cited bemg contemplatedUNITED STATES PATENTS 3 Claims No Drawings 3,087,936 4/1963 LeSucr260/3263 REACTION PRODUCTS OF ALKALI METAL MEBORATE AND HYDROCARBONSUBSTITUTED SUCCINIMIDE CROSS-REFERENCE TO RELATED APPLICATIONS f Thisapplication is a continuation of copending-application Ser. No. 163,542,filed July 14, l97l, now abandoned which in turn was a divisional ofapplication Ser. No. 31,412, filed Apr. 23, 1970, which issued on May20, 1972 as US. Pat. Ndf3,66 6,662.

BACKGROUND OF THE INVENTION l. Field of the Invention In the area oflubrication, there'has been a continuous effort to provide protectionfrom wear and to reduce deposits that form on moving or stationary partsin internal combustion engines. Among additives which have found wideuse as detergents in lubricating oils under a wide variety ofconditions, e.g., automobile gasoline engines and diesel engines, aresuccinimides of alkylene polyamines. These succinimides have been reported in numerous patents and have proven to be extremely efficient inmaintaining deposits dispersed in oil.

The succinimides, however, provide little if any wear protection. Wearcan occur in a variety of areas, by a variety of mechanisms, e.g.',corrosion, adhesion, and abrasion. There are numerous chemicals whichoperate in a variety of ways to reduce wear. Compounds containinghalogenaphosphorus, or sulfur are believed to react with the surface toprovide a surface which wears more slowly than would occur in theabsence of these compounds. Carboxylic acids have been employed whichmay be adsorbed onto the surface to provide a protective layer. Zinccompounds are also used, which under certain conditions form anonsacrificial layer to protect the original surface.

Also, since acids are frequently formed in internal combustion engines;hydrohalide acids in automobile engines and sulfuric acids in dieselengines, sources of base are added to neutralize such acids and preventthem fromcorroding the metal. Various sources include overbasedsulfonates, phenates, and phosphonates.

2. Description of the Prior Art US. Pat. Nos. 3,087,936, 3,344,069, and3,449,362 teach succinimides of alkylene polyamines or polyureas incombination with boric acid, boric acid esters and borohalide complexes.The combinations of the succinimides and boric acid derivatives aretaught as having dete'rgency, rust inhibition, corrosion inhibition,extreme pressure activity, antiwear activity, as well as useful forpesticides and plasticizers. U.S. Pat. No., 3,087,936 (column 2I, lines2630). See also US. Pat. I

US. Pat. No. 3,281,428 teaches the use of succinimides of amines otherthan alkylene polyamines in combination with a variety ofboricacidderivatives, in-

cluding in addition to those mentioned above. the ammonium salts of suchboron acids. See also US. Pat.

with complex forming metal compounds.Illustrative; 65

ence of a small amount ofa dispersant such as a succinimide orsulfonate: These borates are prepared in amorphous form in an oil mediumand provide extreme pressure activity.

VSILJMMARYQOFTHE INVENTION N'ovel compositions are prepared by reactingat'elevatedtemperatures at least 0.8 mols of an alkali metalmetaborateper mol of .a succinimide of an alkylene polyamine to formanalkali metal succinanatecomposition which forms a stable dispersion ina hydrocarbon oil medium. The reaction is carried out in the presence ofa hydroxylic compound, e.g., water, -usually at least about 4 molslofthe hydroxylic compound per mol of the alkali metal metaborate beingpresent. The compositions find use in lubricating oils for internalcombustion engines, providing detergency and dispersancy as well asprotection from wear, not only by acid neutralization, butalso byprotecting from corrosion, abrasive and adhesive wear.

DETAILED DESCRIPTION OF THE INVENTION The novel compositions of thisinvention are alkali metal succinamates prepared by the reaction of analkali metal metaborate and a succinimide of an alkylene polyamine inthe presence of a hydroxylic solvent. Preferred in combination with thiscomposition is an excess of alkali metal metaborate of fromabout l to 20mols, more usually from about 2 to 12 mols.

In the reaction to form the succinamate salt, the fate of the metaborateresiduejs not certain. It may become chemically combined with thesuccinamate salt or become a boron oxide derivative whichremains'dispersed in the medium. -l i t I The compositions of thisinvention may. therefore,be

considered to have the following formula:

wherein? I r M is an alkali metal of atomic number I l to-l 9 (sodium orpotassium), preferably sodium;

one of R and R is hydrogen and the other is ahydrocarbon group of atleast about 50 carbon atoms and usually not morethan about 300 carbonatoms, more usually from about 60 to 200. carbon atoms;

U is alkylene of from 2 to ocarbon atoms more usu- Y is the boron oxideresidue from the reaction of the metal metaborate with the succinimide;and X is amino; succinimide'of the formula;

wherein R and R have beenpreviously defined; or suc cinamate of theformula:

wherein R, R and M have been defined previously.

When greater than I mol of the alkali metal metaborate is employed permol of a monosuccinimide or greater than two mols of an alkali metalmetaborateis employed per mol of a bis-succinimide. the resultingcomposition will have the following formula:

wherein R. R, M, U. n, and Y are as defined previously; and X is amino.or succinamate of the formula:

amal am:

l amemiwherein R, R and M are as defined previously;

p is 1 when X is amine and 2 when X is succinamate;

q is an integer or fractional number averaging over the entirecompositions in the range of from O to 4, usually 1 to 3; and

r is in the range of from 1 to 20, preferably 2 to 12.

The group designated Y, from the nature and stoichiometry of thereaction, is most likely a borate, the boron oxide residue forming boricacid which forms an ammonium salt with the succinamate. In the presenceof excess alkali metal metaborate, the boron oxide residue will probablybe involved in a complex manner, with the excess alkali metal metaboratedispersed in the oil.

The hydrocarbon groupR or Rwill be an oil solubilizing group usuallyaliphatic. having one branch for 6 carbon atoms along the chain, andmore usually about one branch for from 1 to 4 carbon atoms along thechain. The branches will normally be of from 1 to 2 carbon atoms. moreusually of 1 carbon atom, i.e., methyl. There may be from to 2 sites ofolefmic unsaturation as the only unsaturation.

Illustrative hydrocarbon groups are polypropenyl, polyisobutenyl.poly-l-butene, poly-4-methylpentenel, copolymer of ethylene andisobutylene, etc. These compositions are normally prepared bypolymerizing or copolymerizing olefins of from 2 to 6 carbon atoms,ethylene being copolymerized with an olefin of from 3 to 6 carbon atoms.The copolymers are normally random. The preferred polymers arepolypropyleneand polyisobutylene.

The alkali metal metaborates which are present in conjunction with thesuccinamates will generally be either sodium or potassium metaborate,normally having from 0 to 4 waters of hydration. more usually of from Ito 3 waters of hydration.

The alkylene group designated by U. which is of from 2 to 6 carbonatoms. may be straight chain or branched. but will usually be straightchain. Illustrative alkylene groups are ethylene, propylene, 1.2-

propylene, tetramethylenc;'hexamethylene, etc. The preferred alkylenegroupsare of from 2 to 3 carbon atoms, there being Z-carbon atomsbetweenthe nitrogen atoms.

The succinimides, which are used in the preparation of the compositionsof this invention have the following formula: I

2 n -cn- 2 atumn 11x n -cnn 1 wherein:

one of R and R is hydrogen and the other is a hydrocarbon group of fromto 300 carbon atoms, more usually of from to 200 carbon atoms;

' U is alkylene of from 2 to 6 carbon atoms, more usually of from 2 to 3carbon atoms, there being at least 2 carbon atoms between the nitrogenatoms;

n is an integer of from 0 to 6, more usually in an integer of from 1 to5; and X is amino or of the formula:

a ert- B wherein R and R are as defined previously. The illustrativedescription of R and R will also suffice for R and R The alkali metalmetaborates which are employed in this invention will have the followingformula:

wherein M is sodium or potassium; and q is a number of from 0 to 8. moreusually of from 4 to 8.

'In preparing the compositions of this invention, the succinimide willconventionally be used in a suitable medium, e.g., a hydrocarbon medium.Suitable hydrocarbon media, in view of the use intended for thesecompositions, will normally be an oil of lubricating viscosity. Theseoils may be paraffinic, naphthenic or aromatic, or combinations thereof,but are preferably predominantly paraffmic.

The succinimide will generally be employed in solution in from about l()to 60 weight per cent, more usually in from about 15 to 50 weight percent. Conveniently.the solution is heated to a temperature of at leastl50F., preferably to a temperature of from about 175 to about 30()F.,more usually to a temperature of from about 175 to 250F. before theintroduction of the alkali metal metaborate.

To the succinimide solution is then added the alkali metal metaborate,normally dissolved in a hydroxylic solvent. The preferred hydroxylicsolvent is water, although an alcohol of from 1 to 3 carbon atoms may beemployed normally as mixtures with water. Usually, the alkali metalmetaborate solution will be heated to the highest temperaturepermissible, depending on the solvent. Temperatures will, therefore,vary from a low of about 100F. to a high of about 200F. Theconcentration of the alkali metal metaborate in the hydroxylic solventwill normally be from about l5 to 80 weight per cent, more usually fromabout 25 to weight per cent. There will be at least 4 mols of water permol of metaborat e. While the maximum amount of water or alcohol is oneof convenience, usually there will not be more than about 20 mols, moreusually not more than about mols of water and/or alcohol per mol ofmetaborate.

While at least about 0.8 mols of alkali metal metaborate will be usedper mol of succinimide. the total num' ber of mols of metaborate willnot exceed 22 mols per mol of succinimide. Alkali metal metaborate maybe added after the completion of the reaction to further augment themetaborate initially added. Therefore. during the reaction the amount ofmetaborate added will usually not exceed about mols per mol ofsuccinimide.

Vigorous agitation should be employed during the addition and subsequentto the addition of the alkali metal metaborate. Any high speed and,preferably, high shearing device may be used to provide the necessaryagitation. After adding the alkali metal metaborate, the temperature isnormally raised, usually not to exceed 400F., more usua-ly not to exceed300F., and preferably in the range of 250 to 300F. The reaction iscarried out for a time sufficient to drive off a substantial amount ofthe water. Normally, from about to 100 per cent, usually not more than9071 of the water initially introduced (both as solvent and water ofhydration) will be driven off. The amount of water remaining will besufficient to provide the 0 to 4 Waters of hydration for the inorganicboron present in the so lution.

When the desired amount of water has distilled over, the heating isstopped and the reaction mixture is allowed to cool. Since the reactionmixture is normally formed as a concentrate, it can then be suitablydiluted to be usedin lubricating oil compositions.

With excess alkali metal metaborate, high alkalinity values can beachieved. The preferred compositions of this invention will normallyhave alkalinity values of from about at least 50 to 300 mg. KOH/gram,more usually alkalinity values of from about 100 to 250, and preferably150 to 250.

The following examples are offered by way of illustration and not by wayof limitation.

EXAMPLE I Into a Waring blender equipped with a heating jacket. athermometer and stirring motor was charged 400 grams of a weight percent solution in neutral oil of a polyisobutenyl succinimide oftetraethylene pentamine (polyisobutenyl group of about 1,000 viscosityaverage molecular weight) (70 N, 2.1, alkalinity value, 22 mg. KOH/gram)and 3 drops ofa foam inhibitor (DC-200 supplied by Dow Corning Company).The oil solution was heated to about 200F. with stirring. To thesolution was then added 213 grams of sodium metaborate tetrahydrate in107 ml. of distilled water. With continual stirring, the temperature wasraised from 210 to about 300F. over a period of 2 hours and thenmaintained at that temperature for an additional half hour.

At the end of this time, the product was isolated and analyzed. Per centN, 1.54, 1.51; alkalinity value, 201, 204 mg. KOH/gram.

EXAMPLE ll Into a Waring blender was charged 400 grams ofbispolyisohutenyl succinimide of triethylene tetramine (polyisolwtenylof about 1,000 viscosity average mo- EXAMPLE lll Following the procedureof Example II, to 400 grams of a 40 weight per cent solution ofbis-polyisobutenyl succinimide of tetraethylene pentamine in a neutraloil (one polyisobutenyl group is of about 1,000 viscosity averagemolecular weight and the other polyisobutenyl group is about 650viscosity average molecular weight) (7: N, 1.27; alkalinity value, 22mg. KOH/gram) was added I 13.5 grams of sodium metaborate tetrahydratein 57 ml. of distilled water. At the end of the reaction. after cooling,the product was analyzed. 71 N, 1.09; alkalinity value. 120 mg KOH/gram.

Succinamate salts may be used with a wide variety of hydrocarbonlubricating oils, usually derived from pctroleum or preparedsynthetically. The mineral lubricating oils may be paraflinic,naphthenic. asphaltic, or compositions thereof, while the synthetic oilswill normally be polymers of low molecular weight olefins. Lu bricatingoils generally have viscosities of from about 35 to 50,000 SayboltUniversal Seconds (SUS) at The above oils may be used individually ortogether. whenever miscible or made so by the use of mutual solvents.

The compositions of this invention will be employed in lubricating oilsin from 0.5 to 60 weight per cent. When in use in an internal combustionengine, the concentration will vary from 0.5 to 20 weight per cent.Concentrates will vary from 10 to 60 weight per cent, more usually 20 to50 weight per cent.

Other additives are normally included in the oil along with thedetergent antiwear additive of this invention. These additives includepour point depressants, oiliness agents, anti-oxidants, rust inhibitors,additional an tiwear additives, such as bearing corrosion inhibitors,extreme pressure-agents, as well as detergents and additional sources ofalkalinity value. The individual additives will normally vary in amountfrom about 0.01 to 5 weight per cent of the total composition used inthe engine. In concentrates, the weight per cent of these additives willusually range individually from about 0.3 to 10 weight per cent.

Two additives of particular value are dithiophosphate and terephthalicacid. Included in the lubricating oils are from about 1 to 50 mM/kg,preferably 5 to 30 mM/kg, of an 0,0-dihydrocarbyl phosphorodithioate,particularly the zinc salt, wherein the hydrocarbyl groups are of fromabout 4 to 36 carbon atoms. Usually, the hydrocarbyl groups will bealkyl or alkaryl. Other phosphorodithioates, such as trialkyl orpolyethyleneoxy dihydrocarbyl phosphorodithioate may also be used withadvantage.

Terephthalic acid, which may be used, gives greatly enhanced antiwearprotection, and will normally be present in from 0.01 to 0.5, moreusually from about 7 005 to 0.2 weight per cent of the totalcomposition.

In order to demonstrate the effectiveness of thesub- The tests employoil formulations which simulate or are substantially the same as thoseused commercially except forthe presence of the exemplary additives andsuch changes necessitated by its presence.

Two tests were carried .out to demonstrate the detergency of the subjectcompositions, one in an automobile internal combustion engine and theother in a diesel enginev The first test was a Sequence VB engine testwhich is described in Schilling, Moro!" Oils and Engine Lubrication,Scientific; Publications (OB) (1968), 3.35. In this formulation, a 100neutral oil was compounded with 12 mM/kg of zinc dialkyl dithiophosphate(alkyl of from 4-to 5 carbon atoms), 16 mM/kg based on calcium ofanoverbased calcium sulfonate, 1.6 weight: percent of sodiumpolyisobutenyl succinamate of tetraethylene;pentamine (polyisobutenyl ofabout 1,000 viscosity average: molecular weight), and 0.25 weight percent of sodium metaborate. (approximately a 4:1 mol ratio of-metaborateto succinamate).

The results are reported for piston varnish 0 to 10, 10 being clean. Fortotal varnish and sludge, 0 to 50, 50 being clean. The above indicatedoil had the following ratings: Piston varnish 8.9; total varnish 41.9;sludge 44.1. These results demonstrate that the succinamate is aneffective detergent in an automobile internal combustion engine.

ln-the Caterpillar l-H test, the test was carried out for 120 hours; Ina mid-continent 200 neutral oil was formulated 1.8 weight per cent of anethylene/propylene copolymerviscosity index improver (V- 92 SUS), 6.67mM/kg of aneutral calcium sulfonate, 16.7 mM/kg of a sulfurisedcalciu'rn polypropylene phenate having about; a 1.121 calcium ratio tostoichiometric, 4.7 mM/kg of zinc 0,0-dialkylphenyl dithiophosphate(alkyl of from 12 to 15 carbon atoms), 7.3 mM/kg of zinc 0.0-dialkyldithiophosphate (alkyl of from 4 to 5 carbon atoms), 2 weight per centof the sodium succin amate, described in Example 1 with 0.5 weight percent of sodium metaborate, a mol ratio of about 8.1. The engine test wascarried out for 120 hours and the results are reported as follows:Grooves. 0 to 100, 100 indicating no filling of the grooves; lands, 0 to800, 0 being clean; and underhead 0 to l0, 10 being clean. For the aboveformulation, the results were as follows: Grooves, 16, 2.2, 0.7, 0. 7;lands, 185, 35, underhead, 9.1.

For comparison purposes, a like formulation which did not employ thesuccinamate, but rather the same amount of succinimide used to form thesuccinamate and had no sodium metaborate present, the results were asfollows: Grooves, 64, 0.8, 0.6, 0.6; lands, 155,

30, underhead, 7.1. The results clearly show that r the succinamate incombination with sodium metaborate is an effective detergent under theextremely hot conditions of the diesel engine. 1

To demonstrate the effect on wear, a number of tests were also carriedout. The first test was the L-38 Engine Test, which is described inSchilling, supra. 4.31. The oil employed as a base oil was a 480 neutraloil. It was formulated with 9 mM/kg of sine 0,0-dialkyl dithiophosphate(alkyl of from 4 to 5 carbon atoms), 2.2 weight per cent of sodiumsuccinamate described in Example 1. and 0.25 weight per cent of sodiummetaborate. The test duration is 40 hours, and the bearing I 8 weightlossat the end of this time was 82.3 mg. By comparison. using thesuccinimide in the same amount as the succinamate and in the absence ofany sodium metaborate, the bearing weight loss was 148.8 mg. When 0.1weight per cent of terephthalic acid was added to the sodium metaboratecontaining oil, the result was 22.5 mg. weight loss.

A further test, which is extremely severe as an antiwear test, is theFord Valve Train Wear Test. The engine employed is a 1967-1968 Ford, 240CID sixcylinder engine equipped with a single barrel carbure tor with ablocked throttle to prevent engine speed from exceeding 1050 RPM, aclosed crankcase filtration system and an oil filter. Additionally, aheating system is employed inthe oil pan to provide a temperature of theheating element of approximately 267F. To provide enhanced severity inthe valve train the valve springs are overloaded 21%. A normal leadedfuel is employed.

The engine is thoroughly flushed to remove any traces of prior additivesand then filled with 5 quarts of test oil. The spark advance is set at 6BTDC at 1000 RPM and the engine is run with no load for a total runningtime of 60 hours. Speed is maintained at 1000 RPM, oil temperature at220F. and exit water temperature at 200F. Two 4 07.. samples are takenduring the test, one at 30 hours and one at 60 hours. At the end of therun, the valve tips are examined by profilometer and the profilometertraces are measured by planimeter to determine the Cross sectional area.

In this test, the base oil was a /200 mid-continent base stock,containing 7.4 weight per cent of an acrylate detergent viscosityimprover, 40 v mM/kg of an overbased calcium sulfonate (9.9;1 calciumratio) 9 mM/kg of Zinc o,o-dialkyl dithiophosphate (alkylof from 4 to 5carbon atoms) and 1.3 weight per cent of the sodium succinamatedescribed in Examplel. \j arying amounts of sodium succinamate wereemployed. The results are reported in per cent reduction in tip wearrelative to the reference oil which uses the succinimide in place of thesuccinamate and sodium metaborate. At 0.25 weight per cent of sodiummetaborate, there was a 58 weight per cent reduction in tip wear, whileat 0.50 weight per cent sodium metaborate, there was a 51 weight percent reduction.

When the zinc dithiophosphate was replaced with a different zinc dialkyldithiophosphate, differing only in the structure of the alkyl groups,and at the same concentration, with 0.50 weight per cent of sodiummetaborate, 71 per cent reduction in tip wear was achieved.

In addition, the compositions of this invention are found to beeffective additives against rust and other types of wear.

ltis evident from the above results that the succinamates of thisinvention, particularly in combinations with excess alkali metalmetaborates, are extremely effective additives in not only providingdetergency which has been previously known for succinimides, butproviding antiwear and an alkalinity source. The additives arecompatible with a wide variety of other additives normally included inlubricating oils and provide bright. compounded oil compositions. Thepresence of the succinamate as a detergent, provides desirablerelatively low ash formulated compositions.

lclaimzm l. product produced by reacting an alkali metal metaborate .ofthe formula;

wherein M is sodium or potassium and q is a number from U to 8; and asuccinimidc of the formula:

n is an integer of from (i to (a; and

X is amino: in a moi ratio of from 0.8 to 22 mol of said mctahoratc permol of said succinimidc. in the presence of at least 4 mols of water permol of said metaborutc. at a temperature of about I()U-4U()F for a timesufficient to drive off 20-1007: of water 2. The product of claim 1wherein R or R is of from to 200 carbon atoms. U is of from 2 to 3carbon atoms and n is from i to 5.

3. The product of claim 1 wherein R or R is a polyisobutyl group. saidmetaborate is sodium metaborate tetrahydrate and said succinimide is asuccinimide of tetraethylene pentamine.

1. THE PRODUCT PRODUCED BY REACTING AN ALKALI METAL METABORATE OF THEFORMULA:
 2. The product of claim 1 wherein R or R1 is of from 60 to 200carbon atoms, U is of from 2 to 3 carbon atoms and n is from 1 to
 5. 3.The product of claim 1 wherein R Or R1 is a polyisobutyl group, saidmetaborate is sodium metaborate tetrahydrate and said succinimide is asuccinimide of tetraethylene pentamine.